Sulfameter (sulfamethoxydiazine, Sulla) is a safe Iong-aeting sulfonamide of low toxicity. It can maintain blood and urinary sulfonamide levels, with 5 per cent acetylation in the blood and 20·30 per cent acetylation in the urine. The dosage is 500 mg three times daily for the first day, followed by a maintenance dosage of 500 mg daily for two weeks.Good clinical and bacteriological results have been reported from both Europe and the United States in the treatment of respiratory infections, urinary-tract infections, ear, nose and throat infections, and skin infections including pustular acne vulgaris. Sulfamethoxydiazine also can be used as a suppressive drug for as long as nine months in the management of chronic urinary-tract infections, with no adverse side effects.